Browsing by Author "Stauffer, JR"

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    The formation and evolution of planetary systems: First results from a Spitzer Legacy Science Program
    (University of Chicago Press, 2004-09) Meyer, MR; Hillenbrand, LA; Backman, DE; Beckwith, SVW; Bouwman, J; Brooke, TY; Carpenter, JM; Cohen, M; Gorti, U; Henning, T; Hines, DC; Hollenbach, D; Kim, JS; Lunine, J; Malhotra, R; Mamajek, EE; Metchev, S; Moro-Martin, A; Morris, P; Najita, J; Padgett, DL; Rodmann, J; Silverstone, MD; Soderblom, DR; Stauffer, JR; Stobie, EB; Strom, SE; Watson, DM; Weidenschilling, SJ; Wolf, S; Young, E; Engelbracht, CW; Gordon, KD; Misselt, K; Morrison, J; Muzerolle, J; Su, K; University of Arizona; California Institute of Technology; National Aeronautics & Space Administration (NASA); NASA Ames Research Center; Space Telescope Science Institute; Johns Hopkins University; Max Planck Society; University of California System; University of California Berkeley; National Optical Astronomy Observatory; University of Rochester; University of Alabama Tuscaloosa
    We present 3-160 mum photometry obtained with the Infrared Array Camera (IRAC) and Multiband Imaging Photometer for Spitzer (MIPS) instruments for the first five targets from the Spitzer Space Telescope Legacy Science Program "Formation and Evolution of Planetary Systems'' and 4-35 mum spectrophotometry obtained with the Infrared Spectrograph (IRS) for two sources. We discuss in detail our observations of the debris disks surrounding HD 105 (G0 V, 30+/-10 Myr) and HD 150706 (G3 V, similar to700+/-300 Myr). For HD 105, possible interpretations include large bodies clearing the dust inside of 45 AU or a reservoir of gas capable of sculpting the dust distribution. The disk surrounding HD 150706 also exhibits evidence of a large inner hole in its dust distribution. Of the four survey targets without previously detected IR excess, spanning ages 30 Myr to 3 Gyr, the new detection of excess in just one system of intermediate age suggests a variety of initial conditions or divergent evolutionary paths for debris disk systems orbiting solar-type stars.
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    Spitzer Space Telescope observations of G dwarfs in the Pleiades: Circumstellar debris disks at 100 Myr age
    (University of Chicago Press, 2005-10) Stauffer, JR; Rebull, LM; Carpenter, J; Hillenbrand, L; Backman, D; Hines, DC; Soderblom, DR; Mamajek, E; Morris, P; Bouwman, J; Strom, SE; California Institute of Technology; National Aeronautics & Space Administration (NASA); NASA Ames Research Center; University of Arizona; Space Telescope Science Institute; Max Planck Society; National Optical Astronomy Observatory; University of Alabama Tuscaloosa
    Fluxes and upper limits in the wavelength range from 3.6 to 70 mu m from the Spitzer Space Telescope are provided for 20 solar-mass Pleiades members. One of these stars shows a probable mid-IR excess, and two others have possible excesses, presumably due to circumstellar debris disks. For the star with the largest, most secure excess flux at MIPS (Multiband Imaging Photometer for Spitzer) wavelengths, HII 1101, we derive log (L-dust/L-*) similar to -3.8 and an estimated debris disk mass of 4.2 x 10(-5) M-circle plus for an assumed uniform dust grain size of 10 mu m. If the stars with detected excesses are interpreted as stars with relatively recent, large collisional events producing a transient excess of small dust particles, the frequency of such disk transients is similar to 10% for our similar to 100 Myr, Pleiades G dwarf sample. For the stars without detected 24-70 mu m excesses, the upper limits to their fluxes correspond to approximate 3 sigma upper limits to their disk masses of 6 x 10(-6) M-circle plus using the MIPS 24 mu m upper limit or 2 x 10(-4) M-circle plus using the MIPS 70 mu m limit. These upper limit disk masses (for "warm" and "cold" dust, respectively) are roughly consistent with, but somewhat lower than, predictions of a heuristic model for the evolution of an "average" solar-mass star's debris disk based on extrapolation backward in time from current properties of the Sun's Kuiper Belt.